This invention relates to tools, and more particularly to an improved ratchet handle for socket wrenches or similar tools.
Ratchet handles for tools of this general kind have long been available, as for example, from U.S. Pat. Nos. 2,058,855; 2,957,377; 3,019,682; and 685,698. They are required by mechanics and workmen who must manipulate tools in cramped or relatively inaccessible locations where insufficient operating rom is available for movement of tools not equipped with the ratchet feature. The ratchet handles have conventionally been provided with any of a variety of small levers or dials to be operated by the user in order to change the direction of effective movement of the tool driver components of the handle. These levers have bee located in various positions for operation by the workman's fingers. No matter how accessible they may be, however, manipulation of these levers or dials almost always requires use of the workman's "free" hand, or else release of his grip on the ratchet handle.
Generally, the workman cannot conveniently remove his grip on the handle without losing the precise positioning of the tool which may be important to the operation in which the workman is engaged. The so-called "free" hand may be very vitally engaged in holding some other article necessary to the operation. The entire problem is aggravated by the restricted or cramped position often available to the workman, and also by the presence of slippery oils and releases which frequently coat the tools and handles when the direction change is to be made.
To overcome these problems, ratchet tool handles have been developed which permit a change in the direction of effective drive by a mere twist of the workman's wrist. See for example. U.S. Pat. No. 3,608,402. However, such devices have been previously locked by action of a springy projectile for biasing wedge members without or away from cam surfaces at one side or the other of the housing itself. The yieldable character of these spring members fail to provide adequate and secure locking of the rotor and require the locking positions for adjustment at 180 degree turns or the like. Such tools require an excessive number of parts, are cumbersome to manufacture, and are inconvenient to use in restricted places where a 180 degree turn of the workman's wrist is impractical.
More recently, U.S. Pat. No. 4,869,138 describes a more simple and more secure ratchet tool whose novel rotary lock construction permits operational change of direction upon a 45 degree turn of the shaft from its neutral position, which patent is herewith incorporated by reference. Nevertheless, the drawbacks to this device are that its ball member, which is received by a coil spring to assert engaging pressure against the rotary lock, operates somewhat inconsistently. There is the risk that the ball can occasionally slip out of position, thus preventing the otherwise free change of direction of rotation of the wrench. A more secure member to engage the rotary lock would represent a welcomed advancement in the manufacture of this tool. Furthermore, in the operation of this prior art ratchet tool, excessive pressure in twisting the handhold can force the rotary lock beyond a 45 degree turn and again freeze-up the wrench.